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Two Construction Workers Die Inside Sewer Manhole in Indiana

FACE 8767

Introduction:

The National Institute for Occupational Safety and Health (NIOSH), Division of Safety
Research (DSR) is currently conducting the Fatal Accident Circumstances and Epidemiology
(FACE) Project, which is focusing on selected work-related fatalities.

On July 21, 1987, a worker for a construction company entered a seven foot deep sewer
manhole that had a toxic and oxygen deficient atmosphere. When the worker collapsed,
another worker entered the manhole in a rescue attempt and also collapsed. Both workers
were pronounced dead at the scene.

Contacts/Activities:

Officials of the Occupational Safety and Health Administration for the State of Indiana
notified DSR concerning the fatalities and requested technical assistance. This case has
been included in the FACE Project. On September 16, 1987, a DSR research team (a research
industrial hygienist and a safety specialist) met with the company owner, interviewed
workers, and visited and photographed the accident site.

Overview of Employer's Safety Program:

The employer in this incident is a family owned construction company with approximately
50 workers (mostly laborers and heavy equipment operators). The majority of the company
business involves general excavation and the construction of water systems, sewers, and
roads. The company has a written, one-page safety policy which addresses employee
responsibility, general safety guidelines, confined space safety, and reporting injuries.

It is the responsibility of each employee to read this policy. All management level
employees are trained in cardiopulmonary resuscitation (CPR). other than the CPR training,
there is no formal classroom safety instruction for employees. Tool box meetings are held
monthly to discuss basic safety issues. on-the-job safety is the responsibility of each
employee.

No training is given on confined space entry; however, company policy requires that
each manhole be tested and ventilated prior to entry. The company has gas monitoring
devices available at the main office to test confined spaces for oxygen (02), hydrogen
sulfide (H2S), and methane (CH4) . It should be noted that the company also experienced a
confined space fatality five years prior to this incident.

Synopsis of Events:

On July 21, 1987, at approximately 11:00 a.m. a company work crew (a 36 year-old
foreman with 17 years experience with the company, a 50 year-old heavy equipment operator
with 21 years experience with the company, and two laborers) began clearing brush in a
vacant field in preparation for setting grade stakes to extend an existing sewer line for
a new housing subdivision. At 11:30 a.m. when the two laborers broke for lunch, the
foreman and equipment operator both left to look for an existing sewer manhole.

Although there were no eye witnesses to the incident, it is presumed (based on
circumstantial evidence) that the following occurred: The foreman and equipment operator,
upon locating the sewer manhole, removed the manhole cover. In an effort to check the
existing sewer grade, the foreman then entered the seven foot-deep manhole through a 24
inch diameter "manway" opening, and collapsed at the bottom. In an attempt to
rescue the downed foreman, the equipment operator entered the manhole and also collapsed.

After lunch, when the foreman and equipment operator did not return to the field that
was being cleared, the two laborers began to search for them. At approximately 1:30 p.m.
the two laborers found the foreman and equipment operator at the bottom of the manhole
with their heads submerged in about 12 inches of water. One of the laborers told two other
company workers (who had just arrived at the scene) to call for an ambulance. When the
rescue squad from the local fire department arrived (after approximately 15 minutes), two
fire department rescuers, donned self-contained breathing apparatus (SCBA's), entered the
manhole and, using ropes and harnesses, removed the two victims from the manhole.

Fire department and emergency medical service (EMS) personnel noted that the two
victims were "obviously dead", and they were pronounced dead at the scene by the
county coroner. After the victims were removed from the manhole, the atmosphere of the
manhole was tested by a private analytical laboratory and by the City Water Pollution
Control Maintenance Department. Results of these tests are as follows:

Investigator's Comment:

The foreman and equipment operator were both employed by the company five years
previous to this incident when the company experienced its first confined space fatality.

Cause of Death:

Autopsies were performed on both victims. The cause of death for both men was listed as
asphyxiation.

Recommendations/Discussion

Recommendation #1: Employers engaged in the business of sewer construction or
maintenance should assure that workers are trained sufficiently in recognition and
awareness of confined space hazards they may encounter in the daily performance of their
duties.

Discussion: According to the employer, the work being performed at the construction
site did not require the workers to enter any sewer manhole. However, the foreman did
enter the manhole without testing and ventilating the atmosphere of the manhole prior to
entry as required by company safety policy. The fact that this is the second confined
space fatality incident within the last five years (resulting in three confined space
fatalities) underscores the importance of employee training in safe confined space work
practices.

Recommendation #2: The employer should develop and implement a more comprehensive
safety policy with specific procedures for confined space entry.

Discussion: The one page safety policy devotes one paragraph to confined space entry:
"Employees shall not enter manholes, underground vaults, chambers, tanks, silos, or
other similar places that receive little ventilation, unless it has been determined that
the air contains no flammable or toxic gases or vapors. Ventilate thoroughly, detectors
are available at office."

Phrases such as "... unless it has been determined ..." and
"ventilate thoroughly ..." should be expanded and clarified to describe a
detailed confined space entry procedure. Also, the individuals responsible for testing the
atmosphere and making recommendations for safe entry should be identified. Minimally, the
following confined space safe work practices should be addressed in the company safety
policy and implemented on the job:

1. Is confined space entry necessary? Can the task be completed from the outside?

2. Has a company safe entry permit been issued?

3. If entry is to be made, has the air quality in the confined space been tested?

Oxygen supply at least 19.5%

Flammable range less than 10% of the lower flammable limit

Absence of toxic air contaminants

4. Have employees and supervisors been trained in selection and use of personal
protective equipment and clothing?

Protective clothing

Respiratory protection

Hard hats

Eye protection

Gloves

Life lines

Emergency rescue equipment

5. Have employees been trained for confined space entry?

6. Have employees been trained in confined space rescue procedures?

7. If ventilation equipment is needed, is it available and/or used?

8. Is the air quality tested when the ventilation system is operating?

The two fatalities would have been prevented if these recommendations had been
followed. Specific recommendations regarding safe work practices in confined spaces can be
found in NIOSH publications 80-106, "Working In Confined Spaces", and 87-113,
"A Guide to Safety in confined Spaces".